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[Blind75] Best time to buy and sell stock

121. Best Time to Buy and Sell Stock #Array #Dynamic Programming #blind75/2 problem You are given an array prices where prices[i] is the price of a given stock on the ith day. You want to maximize your profit by choosing a single day to buy one stock and

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[Blind75] Two Sum

1. Two Sum #Array #Hash_table #blind75/1 problem Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same

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LeetCode 2073 solution

2073. Time Needed to Buy Tickets #Easy #Queue problem There are n people in a line queuing to buy tickets, where the 0th person is at the front of the line and the (n - 1)th person is at the back of the line. You are given a 0-indexed

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LeetCode 1700 solution

1700. Number of Students Unable to Eat Lunch #Easy #Queue problem The school cafeteria offers circular and square sandwiches at lunch break, referred to by numbers 0 and 1 respectively. All students stand in a queue. Each student either prefers square or circular sandwiches. The number of sandwiches in the

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LeetCode 678 solution

678. Valid Parenthesis String #Medium #stack #dp problem Given a string s containing only three types of characters: '(', ')' and '*', return true if s is valid. The following rules define a valid string: * Any left parenthesis '(' must have a corresponding right parenthesis '

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LeetCode 1249 solution

1249. Minimum Remove to Make Valid Parentheses #Medium #stack problem Given a string s of '(' , ')' and lowercase English characters. Your task is to remove the minimum number of parentheses ('(' or ')', in any positions) so that the resulting parentheses string is valid and

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LeetCode 1544 solution

1544. Make The String Great #Easy #Stack problem Given a string s of lower and upper case English letters. A good string is a string which doesn't have two adjacent characters s[i] and s[i + 1] where: * 0 <= i <= s.length - 2 * s[i]

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LeetCode 1614 solution

1614. Maximum Nesting Depth of the Parentheses #Easy #Stack problem A string is a valid parentheses string (denoted VPS) if it meets one of the following: * It is an empty string "", or a single character not equal to "(" or ")", * It can be written as

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LeetCode 205 solution

205. Isomorphic Strings #Hash_table #String problem Given two strings s and t, determine if they are isomorphic. Two strings s and t are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the

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LeetCode 58 solution

58. Length of Last WordSolved #Easy #String problem Given a string s consisting of words and spaces, return the length of the last word in the string. A word is a maximal  substring consisting of non-space characters only. Example 1: * Input: s = "Hello World" * Output: 5 * Explanation: The

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LeetCode 2958 solution

2958. Length of Longest Subarray With at Most K Frequency #Medium #Array #Hash_table #Sliding_window problem You are given an integer array nums and an integer k. The frequency of an element x is the number of times it occurs in an array. An array is called good if

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LeetCode 713 solution

713. Subarray Product Less Than K #Medium #Array #SlidingWindow problem Given an array of integers nums and an integer k, return the number of contiguous subarrays where the product of all the elements in the subarray is strictly less than k. Example 1: * Input: nums = [10,5,2,6], k

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LeetCode 442 solution

442.  Find All Duplicates in an Array #Array #HashTable problem Given an integer array nums of length n where all the integers of nums are in the range [1, n] and each integer appears once or twice, return an array of all the integers that appears twice. You must write

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LeetCode 1609 solution

1609. Even Odd Tree #Tree #Breadth-First Search #Binary Tree problem A binary tree is named Even-Odd if it meets the following conditions: - The root of the binary tree is at level index 0, its children are at level index 1, their children are at level index 2, etc. -

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LeetCode 513 solution

513. Find Bottom Left Tree Value #Medium #Binary_tree problem Given the root of a binary tree, return the leftmost value in the last row of the tree. python # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.

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LeetCode 543 solution

543. Diameter of Binary Tree #Binary_Tree problem Given the root of a binary tree, return the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not